It is generally accepted that the recreational sport of skateboarding developed as an offshoot of surfing sometime in the late 1960s. As such, the skateboard was, and still is, intended to provide a similar athletic experience to surfing. In recent years, the sport of skateboarding has become popular throughout the industrialized world. This acceptance of the sport is due in large part to technological developments which have improved the ride and handling of skateboards so that they better approximate the smooth ride of a surfboard on water.
At one time, roller skates were commonly provided with trucks similar to the trucks found nowadays on most skateboards. Typically, roller skates of this design had two sets of two wheels mounted on pivoting trucks, with the four wheels being disposed essentially at the corners of a rectangle. This old design has given way in popularity recently to an in-line roller blade configuration, with a plurality of wheels arranged along the median longitudinal axis of the roller skate. An in-line arrangement of wheels provides for more speed and maneuverability than the rectangular arrangement of wheels on pivoting trucks. However, the in-line configuration naturally sacrifices a degree of stability to achieve improved maneuverability.
In its most common current form, a skateboard typically includes a board 6 to 12 inches wide and 18 to 72 inches long. Boards are typically made of wood. Two sets of two polyurethane wheels are typically mounted on the bottom side of the board, one set of wheels being attached towards the front end of the board, the other set of wheels being attached towards the rear end of the board. The rear and front two-wheeled trucks on conventional skateboards are independent and not mechanically connected in any way which results in a skateboard that is relatively difficult to control in turns. Moreover, the turning radius is relatively large because the skateboard trucks are independently acting to accomplish a turn in direction of the tilt of the skateboard.
There is a need for a skateboard design that combines the speed and maneuverability of an in-line wheel arrangement with the handling and stability of laterally disposed wheels. It would be advantageous if such a design with a single wheel in the rear and two wheels in the front would exhibit handling characteristics that better mirrored the handling of a surfboard on water or a snowboard.
Numerous innovations for skateboards have been provided in the prior art that are described as follows. Even though these innovations may be suitable for the specific individual purposes to which they address, they differ from the present design as hereinafter contrasted. The following is a summary of those prior art patents most relevant to this application at hand, as well as a description outlining the difference between the features of the Three-wheeled Skateboard and the prior art.
U.S. Pat. No. 4,795,181 of Robert B. Armstrong describes a skateboard that is comprised of a single oversized centrally-located wheel in addition to conventional pairs of front and rear wheels. The wheels are arranged so that the board will ride on no more than three wheels at a time, with either the front or rear pair being elevated above the supporting ground surface, depending upon the rider's longitudinal weight distribution on the skateboard relative to the center wheel. An optional foot-operated friction brake can engage with the center wheel.
This patent describes a skateboard that is comprised of a single oversized centrally-located wheel in addition to conventional pairs of front and rear wheels but does not use the single wheel in the rear in combination with two wheels in the front along with the mechanical connection between them.
U.S. Pat. No. 5,322,312 of Milton A. Cammack describes a user-propelled vehicle that has a wheelchair embodiment and a three-wheeled skateboard embodiment. In the wheelchair embodiment, a foldable frame has a seat for supporting the user and a propulsor movably attached to the frame for allowing the user to pump the propulsor. The propulsor is engaged with both rear wheels of the wheelchair through independent ratchet-clutch mechanisms for permitting torque to be transferred to one or both wheels when the propulsor is pumped to propel and steer the wheelchair. In the three-wheeled skateboard embodiment, a frame has two wheels mounted in tandem near the front of the frame and a third wheel mounted on the centerline of the frame behind the front wheels. Two pedals are hingedly mounted side-by-side on the frame and are ratchetably engaged with the rear wheel. Each pedal is movable between a thrust position, wherein the front portion of the pedal is raised from the frame, and a rest position, wherein the pedal is flush with the frame. Each pedal is spring-returned to its thrust position. The user can alternately or simultaneously depress the pedals to impart torque to the rear wheel and thereby propel the skateboard.
This patent describes a user-propelled vehicle that has a wheelchair embodiment and a three-wheeled skateboard embodiment. In the wheelchair embodiment, a foldable frame has a seat for supporting the user and a propulsor movably attached to the frame for allowing the user to pump the propulsor. Although this patent describes a three wheeled skateboard it deals mainly with a means of propulsion and does not provide a mechanical connection between the front wheels and the back wheel to create a tighter turning radius.
U.S. Pat. No. 6,428,022 of Yoshi Namiki describes an inline skateboard capable of being propelled by leg motion of a rider and which includes a platform supporting the rider along with a front wheel truck and a rear wheel truck. Each of these wheel trucks carries a single wheel. Moreover, the wheels are capable of slight turning movement transversely with respect to the platform and provide a high degree of maneuverability and turning capability. The wheels on each of the trucks are offset with respect to a pivot axis for each of the trucks. In, addition, the axis of rotation of the front wheel is displaced rearwardly of the front pivot axis and the axis of rotation of the rear wheel is displaced forwardly of the rear pivot axis. Further, the angle of displacement of these pivot axes with respect to the axis of rotation is the same. Each of the wheels have relatively flat riding surfaces and relatively flat side walls with arcuate connecting sections extending between the flat side walls and the relatively flat riding surfaces, such that only the outer edges of the wheels are arcuate in shape. This construction provides for highly effective maneuverability and steering capability.
This patent describes an inline skateboard capable of being propelled by leg motion of a rider. The inline skateboards generally have single wheels in the front and rear and are very difficult to operate. This patent does not make use of any mechanical connection between the front wheels and the back wheel.
U.S. Pat. No. 7,083,178 of Steven Dickinson Potter describes a skateboard for use on pavement, ice or snow using a single narrow-footprint wheel, ice-blade or ski-runner attached to each foot, thus requiring the rider to dynamically balance the board. The skateboard is capable of self-propulsion at considerable speed on the flat or uphill by using an undulating motion. It can also lean up to 30 degrees and has a steering circle of only two feet. The board's construction comprises a front footboard, a rear footboard, and a strut which connects the two footboards and resists bending and extension. Each footboard includes a footpad, an attachment (i.e. a wheel, blade or ski), and a pivot joint connecting to the strut. The axis of this joint is aligned perpendicular to the footpad which allows the rider to steer each footboard independently by torsionally rotating the lower leg.
This patent describes a skateboard for use on pavement, ice or snow using a single narrow-footprint wheel, ice-blade or ski-runner attached to each foot. This skateboard again does not make use of any mechanical connection between the front wheels and the back wheel.
U.S. Pat. No. 7,367,572 of Xiancan Jiang describes a skateboard in accordance that includes a footplate having a lower surface, a front wheel and a rear wheel arranged in a front end and a rear end of the lower surface respectively, wherein the wheels are universal, and the footplate includes a front plate and a rear plate. The front plate and the rear plate are connected via a rotatable torsional mechanism, and a restriction element is defined between each plate and the torsional mechanism for restricting the rotation range of the torsional mechanism.
This patent describes a skateboard where rotatable torsional mechanism and a restriction element is defined between each plate and the torsional mechanism for restricting the rotation range of the torsional mechanism. These skateboards do not make use of any mechanical connection between the front wheels and the back wheel to give a quicker action and reduced turning radius.
None of these previous efforts, however, provides the benefits attendant with the Three-wheeled Skateboard. The present design achieves its intended purposes, objects and advantages over the prior art devices through a new, useful and unobvious combination of method steps and component elements, with the use of a minimum number of functioning parts, at a reasonable cost to manufacture, and by employing readily available materials.
In this respect, before explaining at least one embodiment of the Three-wheeled Skateboard in detail it is to be understood that the design is not limited in its application to the details of construction and to the arrangement, of the components set forth in the following description or illustrated in the drawings. The Three-wheeled Skateboard is capable of other embodiments and of being practiced and carried out in various ways. In addition, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for designing of other structures, methods and systems for carrying out the several purposes of the present design. It is important, therefore, that the claims be regarded as including such equivalent construction insofar as they do not depart from the spirit and scope of the present application.